This invention generally relates to printer apparatus and methods and more particularly relates to a printer and media supply spool adapted to sense type of media, and method of assembling same.
Pre-press color proofing is a procedure that is used by the printing industry for creating representative images of printed material. This procedure avoids the high cost and time required to actually produce printing plates and also avoids setting-up a high-speed, high-volume, printing press to produce a single example of an intended image. Otherwise, in the absence of pre-press proofing, the intended image may require several corrections and be reproduced several times to satisfy customer requirements. This results in loss of profits. By utilizing pre-press color proofing time and money are saved.
A laser thermal printer having half-tone color proofing capabilities is disclosed in commonly assigned U.S. Pat. No. 5,268,708 titled "Laser Thermal Printer With An Automatic Material Supply" issued Dec. 7, 1993 in the name of R. Jack Harshbarger, et al. The Harshbarger, et al. device is capable of forming an image on a sheet of thermal print media by transferring dye from a roll (i.e., web) of dye donor material to the thermal print media. This is achieved by applying a sufficient amount of thermal energy to the dye donor material to form the image on the thermal print media. This apparatus generally comprises a material supply assembly, a lathe bed scanning subsystem (which includes a lathe bed scanning frame, a translation drive, a translation stage member, a laser printhead, and a vacuum imaging drum), and exit transports for exit of thermal print media and dye donor material from the printer.
The operation of the Harshbarger, et al. apparatus comprises metering a length of the thermal print media (in roll form) from the material supply assembly. The thermal print media is then measured and cut into sheet form of the required length, transported to the vacuum imaging drum, registered, and then wrapped around and secured onto the vacuum imaging drum. Next, a length of dye donor roll material is also metered out of the material supply assembly, measured and cut into sheet form of the required length. The cut sheet of dye donor roll material is then transported to and wrapped around the vacuum imaging drum, such that it is superposed in registration with the thermal print media, which at this point has already been secured to the vacuum imaging drum.
Harshbarger, et al. also disclose that after the dye donor material is secured to the periphery of the vacuum imaging drum, the scanning subsystem and laser write engine provide the previously mentioned scanning function. This is accomplished by retaining the thermal print media and the dye donor material on the spinning vacuum imaging drum while the drum is rotated past the print head that will expose the thermal print media. The translation drive then traverses the print head and translation stage member axially along the rotating vacuum imaging drum in coordinated motion with the rotating vacuum imaging drum. These movements combine to produce the image on the thermal print media.
According to the Harshbarger, et al. disclosure, after the intended image has been written on the thermal print media, the dye donor material is then removed from the vacuum imaging drum. This is done without disturbing the thermal print media that is beneath the dye donor material. The dye donor material is then transported out of the image processing apparatus by the dye donor exit transport. Additional dye donor materials are sequentially superposed with the thermal print media on the vacuum imaging drum, then imaged onto the thermal print media as previously mentioned, until the intended full-color image is completed. The completed image on the thermal print media is then unloaded from the vacuum imaging drum and transported to an external holding tray associated with the image processing apparatus by the print media exit transport. However, Harshbarger, et al. do not appear to disclose appropriate means for informing the printer of type of donor material loaded into the printer, so that high quality images are obtained.
The previously mentioned dye donor web is typically wound about a donor supply shaft to define a donor spool, which is loaded into the printer. However, it is desirable to match the specific type donor web with a specific printer, so that high quality images are obtained. For example, it is desirable to inform the printer of the dye density comprising the donor web, so that the laser write head applies an appropriate amount of heat to the web in order to transfer the proper amount of dye to the thermal print media. Also, it is desirable to verify that the donor spool is not loaded backwards into the printer. This is desirable because, if the donor spool is loaded backwards into the printer, the donor sheet may be propelled off the rotating drum at high speed or the dye present on the donor material may transfer to a lens included in an optical system belonging to the printer. Either of these results can cause catastrophic damage to the printer, thereby increasing printing costs. For example, a replacement for a damaged lens typically will cost several thousands of dollars. In addition, it is also desirable to know number of frames (i.e., pages) remaining on a partially used donor web. This is desirable because it is often necessary to exchange a partially used roll of donor web for a full roll of donor web for overnight printing, so that the printer can operate unattended. However, unattended operation of the printer requires precise media inventory control. That is, the printer is preferably loaded with a full roll of donor material in order that the printer does not stop printing due to lack of donor material during an unattended extended time period (e.g., overnight printing). Therefore, a further problem in the art is insufficient donor material being present during unattended extended operation of the printer.
Also, in order to properly calibrate the printer, an operator of the printer determines the characteristics of the donor web (e.g., dye density, number of frames remaining on the donor web, e.t.c.) and manually programs the printer with this information to accommodate the specific dye donor web being used. However, manually programming the printer is time consuming and costly. Moreover, the operator may make an error when he manually programs the printer. Therefore, another problem in the art is time consuming and costly manual programming of the printer to accommodate the specific dye donor web being used. An additional problem in the art is operator error associated with manual programming of the printer.
A donor supply spool obviating need to manually program a resistive head thermal printer with frame count information is disclosed in commonly assigned U.S. Pat. No. 5,455,617 titled "Thermal Printer Having Non-Volatile Memory" issued Oct. 3, 1995 in the name of Stanley W. Stephenson, et al. This patent discloses a web-type dye carrier for use in a thermal resistive head printer and a cartridge for the dye carrier. The dye carrier is driven along a path from a supply spool and onto a take-up spool. Mounted on the cartridge is a non-volatile memory programmed with information, including characteristics of the carrier. A two-point electrical communication format allows for communication to the memory in the device. In this regard, two electrically separated contacts disposed within the printer provide a communication link between the printer and cartridge when the cartridge is inserted into the thermal resistive head printer. Moreover, according to the Stephenson et al. patent, communication between the cartridge and printer can also be accomplished by use of opto-electrical or radio frequency communications. Although the Stephenson et al. patent indicates that communication between the cartridge and printer can be accomplished by use of opto-electrical or radio frequency communications, the Stephenson et al. patent does not appear to disclose specific structure to accomplish the opto-electrical or radio frequency communications.
Therefore, there has been a long-felt need to provide a printer with media supply spool adapted to sense type of media, and method of assembling same.